Helvetica chimica acta

α??Alkylation of Amino Acids without Racemization. Preparation of Either (S)??or (R)?螃窿?Methyldopa from (S)??Alanine

D Seebach, JD Aebi, R Naef, T Weber

Index: Seebach, Dieter; Aebi, Johannes D.; Naef, Reto; Weber, Theodor Helvetica Chimica Acta, 1985 , vol. 68, p. 144 - 154

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Citation Number: 80

Abstract

Abstract Enantiomerically pure cis-and trans-5-alkyl-1-benzoyl-2-(tert-butyl)-3- methylimidazolidin-4-ones (1, 2, 11, 15, 16) and trans-2-(tert-butyl)-3-methyl-5- phenylimidazolidin-4-one (20), readily available from (S)-alanine,(S)-valine,(S)-methionine, and (R)-phenylglycine are deprotonated to chiral enolates (cf. 3, 4, 12, 21). Diastereoselective alkylation of these enolates to 5, 5-dialkyl-or 5-alkyl-5- ...